This invention relates to the alleviation of deep venous thrombosis by mechanical as opposed to chemical means. Deep venous thrombosis (DVT) is a condition in which clotting of venous blood occurs in the lower extremities and pelvis because of the lack of sufficient muscular activity in the lower legs. Such clotting can be life threatening if a blood clot migrates to the heart, lung or brain and interferes with blood circulation. Preventive treatment often employs chemical means, such as anti-coagulants; however, such chemical means are often contra-indicated, for example, in neurological surgery or where the threat of hemmorage is present.
In these latter conditions the prevention of DVT has been attempted by mechanical means employing elastic bandages or stockings or by pneumatic leggings adapted to receive a pressured gas in desired sequence. U.S. Pat. No. 3,892,229 illustrates one form of this type of device and U.S. Pat. No. 3,901,221 illustrates a type of pressured sequence.
While devices such as those shown in U.S. Pat. No. 3,892,229 have been employed successfully, it is believed that problems exist therewith. Such problems arise from the fact that pressure is applied equally and simultaneously throughout the entire limb. It is more preferable to force the blood in the extremities back toward the heart. Devices which apply a uniform overall pressure do not move the blood in a specific direction. Furthermore, these devices are made from rubber or plastic material and are quite hot when worn for long periods of time and no means for providing ventilation exist.